According to a purpose of packet data to be transmitted/received by a terminal (e.g., an electronic device such as a smartphone), a wireless communication system may transmit a packet by establishing a Packet Data Network (PDN) connection corresponding thereto and by creating a bearer in the PDN connection. For example, in order to utilize an Internet protocol Multimedia Subsystem (IMS) service, a connection to a packet data network in which IMS-related servers are present is established. In addition, in order to use an Internet service, a connection to a packet data network constituting an Internet network is established.
In addition to the IMS service and the Internet service, various packet data networks may be present for a Voice of Long Term Evolution (VoLTE) service or the like. The terminal may be connected to the various packet data networks to use various services.
Recently, a standardization task for the post LTE technology is underway in a 3rd Generation Partnership Project (3GPP) standardization organization. In the present specification, the aforementioned technique is referred to as “LTE Advanced” or “LTE-A”. One of the primary differences between an LTE system and an LTE-A system is a difference of a system bandwidth. The LTE-A system aims to support a broadband equal to or greater than up to 100 MHz. For this, a carrier aggregation or bandwidth aggregation technique is used in which multiple frequency bands constitute one broadband. That is, the carrier aggregation technique is a technique in which the multiple frequency bands are used as one logical frequency band to use a broader frequency band. Each frequency bandwidth may be defined on the basis of a system bandwidth used in the LTE system.